标题： 核量子效应减缓了生物光捕获复合体中的能量传递 显示英文标题

标题： Nuclear quantum effects slow down the energy transfer in biological light-harvesting complexes

摘要： 我们评估与高频发色团振动相关的量子力学效应对生物光捕获复合物中激发能量传递的影响。 我们从一种混合量子-经典理论开始，该理论以与量子-经典平衡分布一致的方式，将电子运动的量子描述与核运动的经典描述结合起来。 然后，我们通过高频率振动模式的变分极化子变换在此理论中包含核的量子效应。 这种方法通过与完全量子力学基准计算的比较得到验证，然后应用于三个典型的生物光捕获复合物。 我们发现，在量子处理中，高频振动会延迟能量传递，但在经典处理中会加速能量传递。 对于紫色细菌光捕获复合物2中的环间传递，量子处理中的传递速率比经典处理慢1.5倍。 在Fenna--Matthews--Olson复合物中，两种情况下的传递时间尺度基本上相同，而菠菜光捕获复合物II中的传递在量子处理中慢1.7倍。 在所有情况下，经典处理都能很好地再现发色团的量子力学长时间平衡种群，这表明核的量子效应通常对能量传递的方向性影响不大。 然而，核的量子效应确实会降低具有较大激子能隙和强振动耦合到高频振动模式的系统的传递速率。 显示英文摘要

摘要： We assess how quantum-mechanical effects associated with high-frequency chromophore vibrations influence excitation energy transfer in biological light-harvesting complexes. We begin with a mixed quantum-classical theory that combines a quantum description of the electronic motion with a classical description of the nuclear motion in a way that is consistent with the quantum-classical equilibrium distribution. We then include nuclear quantum effects in this theory with a variational polaron transformation of the high frequency vibrational modes. This approach is validated by comparison with fully quantum mechanical benchmark calculations and then applied to three prototypical biological light-harvesting complexes. We find that high-frequency vibrations delay the energy transfer in the quantum treatment, but accelerate it in the classical treatment. For the inter-ring transfer in the light-harvesting complex 2 of purple bacteria, the transfer rate is a factor of 1.5 times slower in the quantum treatment than the classical. The transfer timescale in the Fenna--Matthews--Olson complex is essentially the same in both cases, whereas the transfer in light-harvesting complex II of spinach is 1.7 times slower in the quantum treatment. In all cases, the quantum mechanical long-time equilibrium populations of the chromophores are well reproduced by the classical treatment, suggesting that nuclear quantum effects are generally unimportant for the directionality of energy transfer. Nuclear quantum effects do however reduce the transfer rate in systems with large excitonic energy gaps and strong vibronic coupling to high-frequency vibrational modes.